Seedbed preparation implement having rotary disc with adjustable gang angle

ABSTRACT

A disc gang is provided that is suitable for use as part of a multifunctional seedbed preparation implement or in a standalone disc harrow. The disc gang is configured to permit a gang angle of the disc gang to be adjusted to accommodate differing soil conditions and/or to obtain different tillage characteristics. The disc gang may include a frame mounted on a mainframe of a primary tillage implement such as a cultivator. The frame includes a main beam mounted on the implement&#39;s mainframe and a disc support beam connected to the main beam and supporting a plurality of rotating discs. The gang angle can be infinitely adjusted through a designated range by pivoting one end of the disc gang about a vertical pivot axis while permitting another end portion of the disc gang to slide along a support surface for that end. The disc support beam may also be configured to be raised and lowered relative to the main beam so as to permit the cutting depth of the discs to be adjusted independently of the working depth of the remainder of the implement. The disc gang preferably is modular so as to negate the need for complex mechanical and hydraulic connections between the disc gang and the remainder of the implement.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to seedbed preparation implements and, moreparticularly, relates to a disc gang usable, e.g., on a multifunctionalseedbed preparation implement and having an adjustable gang angle.

[0003] 2. Discussion of the Related Art

[0004] An increasing number of seedbed preparation implements areconfigured to till the soil, level it, and/or break up lumps in a singlepass so as to minimize the number of passes required to prepare a fieldfor planting. Implements of this general type are sometimes known as“multifunctional seedbed preparation implements.” Multifunctionalseedbed implementation implements are gaining popularity becauseminimizing the number of required passes conserves fuel and also reduceswind and water erosion.

[0005] One type of multifunctional seedbed preparation implement is theso-called Combo Mulch Finisher, manufactured, e.g. by Case Corporation.The Combo Mulch Finisher includes a disc harrow having one or more discgangs, a cultivator located behind the disc harrow, and an optionalrotary or tine harrow located behind the cultivator. The threetandem-oriented implement components are configured to partially orcompletely prepare a seedbed for planting, yet leave a high residuecover for maximum conservation efforts. Specifically, the front discharrow aggressively cuts and sizes residue ahead of the cultivator andturns the soil to bury some of the residue. The cultivator shattersclods produced by the disc harrow, mixes the clods with the soil,incorporates chemicals, and returns some of the residue to the surface.The rear harrow, if present, reduces clods and levels ridges left by thecultivator. The working depth of the entire implement can be adjusted byraising or lowering the cultivator mainframe relative to the wheels thatsupport it on the ground. In some implements of this type, the workingdepth of the individual disc gangs of the disc harrow can beindependently adjusted by raising and lowering at least adisc-suspension portion of each disc gang relative to the cultivator.

[0006] Each disc gang typically includes a plurality of concave circularsteel discs with tapered or beveled peripheral edges. The discs,although tending to roll or rotate as they are pulled forward, penetrateinto and break up the soil and stalks and other residue lying on theground. The soil and residue then ride along and across the concavesurfaces so as to be turned or inverted. A portion of the residue isburied with this turning, with the percentage of buried residueincreasing with the amount of soil turning. The amount of soil turningis determined, in part, by the angle of attack of each disc bladerelative to the draft direction, i.e., the direction along which theimplement is being pulled along the field. This angle of attack is knownas the “gang angle” and is defined as the angle of the discs' gang axisrelative to a line extending perpendicularly to the draft direction.Typical gang angles range from 5° to 10°, but other angles are used insome situations.

[0007] It is often desirable to adjust the gang angle in order to set ormaintain a desired amount of soil turning for, e.g., residue managementor tilth management purposes. Residue management comprises controlling aseedbed preparation implement to leave a desired percentage of theseedbed surface covered by crop residue. This percentage typicallyranges from about 30% to about 70%, depending on field conditions andother factors. Proper residue management provides several benefits,including:

[0008] protecting the soil surface from compaction, crusting, anderosion by absorbing the energy of rainfall on the soil;

[0009] building soil organic matter to increase moisture holdingcapacity and expand soil nutrient pool;

[0010] building and strengthening soil aggregates to resist crusting andprovide adequate pore space and water permeability;

[0011] improving water infiltration;

[0012] accelerating soil warming to take full advantage of the growingseason; and

[0013] creating a soil environment needed for higher yields.

[0014] Soil tilth is a measure of the relationship between the soil,air, water, organic matter, and biological activity. Good soil tilth hasapproximately 50% mineral soil and organic matter and about 50% porespace. Maintaining good soil tilth provides several advantages,including:

[0015] maximizing water and air permeability to reduce ponding, run-off,and erosion;

[0016] allowing good early root growth;

[0017] increasing air and water exchange from plant food availability;

[0018] enabling percolation of excess water deep into the soil; and

[0019] enabling roots to penetrate deeper into the soil to providemoisture needed during periods of drought.

[0020] Setting the gang angle at a desired value is one viable method ofobtaining desired residue retention and/or tilth characteristics underprevailing soil conditions and operating speeds. It would be beneficialto adjust that angle to obtain different residue retention and/or tilthcharacteristics under the same operating conditions or to maintain thesame residue retention and/or tilth characteristics as soil conditionsand/or operating speeds vary from area to area or even from field tofield. Hence, incorporating gang angle adjustability into a disc gang ofa multifunctional seedbed preparation implement would considerablyincrease the flexibility and versatility of a disc gang. However, noheretofore known multifunctional seedbed preparation implement employeddisc gangs with adjustable gang angles. This lack is believed to resultfrom impracticalities resulting from the ways in which these machineswere constructed and operated.

[0021] The gang angles of some standalone disc harrows are adjustable,but adjustment is typically either difficult or imprecise. For instance,U.S. Pat. No. 3,080,933 to Kramer, U.S. Pat. No. 4,180,135 toBirkenbach, and U.S. Pat. No. 5,462,123 to Harlan all disclose tandemdisc harrows having front and rear sets of disc gangs, each of whichincludes two disc gangs that have independently adjustable gang angles.Each disc gang of all of these systems includes a rigid frame that ismounted on the mainframe of the disc harrow so as to pivot about avertical axis. Another portion of the frame is mountable on themainframe only at a selected one of a plurality of discreet,spaced-apart mount points, usually taking the form of spaced mountingholes in a plate on the disc harrow's mainframe. As a result of thisconfiguration, the gang angle cannot be adjusted “infinitely”, i.e.,continuously within the range of gang angle adjustment. It instead canbe adjusted only discreetly, with a degree of precision that is limitedby the spacing between the mount points. The resultant configuration hasrelatively low flexibility and versatility. It is also poorly suited foradaptability to disc gangs used in a Combo Mulch Finisher or any othermultifunctional seedbed preparation implement.

[0022] The need therefore has arisen to provide a multifunctionalseedbed preparation implement having disc gangs with adjustable gangangles.

[0023] The need has also arisen to provide a disc gang that is usableeither on a multifunctional seedbed preparation implement or on astandalone disc harrow and that has infinite gang angle adjustcapability, at least over a designated range of gang angle adjustment.

SUMMARY OF THE INVENTION

[0024] In accordance with a first aspect of the invention, amultifunctional seedbed implement includes a disc gang having a gangangle that is adjustable relative to the remainder of the implement. Theimplement includes at least a cultivator and a disc harrow. Thecultivator includes a mainframe configured to be pulled in a draftdirection, and a plurality of ground engaging plow shanks mounted on themainframe. The disc harrow include at least one disc gang including adisc support beam, a plurality of ground engaging discs rotatablysupported on the support beam and configured to rotate about a commonaxis that extends at a disc gang angle relative to a perpendicular tothe draft direction, and a main beam which is attached to the discsupport beam and which is mounted on the mainframe so as to permit thedisc gang to be movable relative to the frame as a unit so as to adjustthe gang angle.

[0025] Preferably, the gang angle is infinitely adjustable within atleast a designated range of, e.g., from about 5° to about 10°.

[0026] The main beam is preferably pivotably mounted on the mainframeadjacent a first end thereof and is mounted on a slotted plate at alocation remote from the first end so as to permit the main beam toslide along a slot in the slotted plate for gang angle adjustment. Anactuator, such as a cylinder or a turnbuckle, is coupled to the discgang and to the mainframe and is manually or automatically actuatable topivot the disc gang about to the mainframe to effect gang angleadjustment.

[0027] In order to permit the cutting depth of the discs to be adjusted,support arms may couple the main beam to the disc support beam and maybe pivotable to raise and lower the disc support beam relative to themain beam.

[0028] In accordance with another aspect of the invention, a disc gangis provided that is configured for attachment to a mainframe of aseedbed preparation implement that is configured to be pulled in a draftdirection. The implement may be a standalone disc harrow or amultifunctional implement such as a Combo Mulch Finisher. The disc gangcomprises a plurality of ground engaging rotary discs and a frame. Thediscs are configured to rotate about an axis that extends at a gangangle relative to a perpendicular to the draft direction. The framesupports the discs and is configured to be connectable to the frame soas to be movable relative to the implement's mainframe so as to permitthe gang angle to be infinitely adjusted through a range of at least 3°.The frame preferably comprises a main beam which is mountable on theimplement's mainframe and a disc support beam. The disc support beam islocated in front of the main beam, is connected to the main beam by aplurality of arms, and supports the discs. Preferably, the arms arepivotable to raise and lower the disc support beam relative to the mainbeam and, thereby, adjust the cutting depth of the discs.

[0029] A method of adjusting the gang angle of a disc gang is alsodisclosed.

[0030] Other objects, features, and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription and accompanying drawings. It should be understood, however,that the detailed description and specific examples, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Preferred exemplary embodiments of the invention are illustratedin the accompanying drawings in which like reference numerals representlike parts throughout, and in which:

[0032]FIG. 1 is a top plan view of a multifunctional seedbed preparationimplement constructed in accordance with a preferred embodiment of theinvention;

[0033]FIG. 2 is a side elevation view of the implement of FIG. 1;

[0034]FIG. 3 is a fragmentary top plan view of a portion of theimplement of FIGS. 1 and 2, including one of the disc gang assemblies ofthat implement;

[0035]FIG. 4 is a front elevation view taken generally along the lines4-4 in FIG. 3;

[0036]FIG. 5 is a side elevation view taken generally along the lines5-5 of FIG. 3;

[0037]FIG. 6 is a sectional elevation view taken generally along thelines 6-6 of FIG. 3;

[0038]FIG. 7 is a sectional elevation view taken generally along thelines 7-7 of FIG. 3 and illustrating portions of the implement inphantom;

[0039]FIG. 8 is a sectional elevation view taken generally along thelines 8-8 of FIG. 3 and illustrating portions of the implement inphantom;

[0040]FIG. 9 is a fragmentary perspective view of the disc gang assemblyof FIG. 3 and adjacent components of the implement; and

[0041]FIG. 10 is a fragmentary, partially exploded top plan view of thedisc gang assembly of FIG. 3 and adjacent components of the implement,illustrating the disc gang assembly removed from the remainder of theimplement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] 1. Resume

[0043] Pursuant to the invention, a disc gang is provided that is wellsuited (but not exclusively suited) for use as part of a multifunctionalseedbed preparation implement and that is configured to permit a gangangle of the disc gang to be adjusted to accommodate different operatingconditions and/or to obtain different tillage characteristics. In oneembodiment, the disc gang includes a frame mounted on a mainframe of aprimary tillage implement such as a cultivator. The frame includes amain beam mounted on the implement's mainframe and a disc support beamconnected to the main beam and supporting a plurality of rotating discs.The gang angle can be infinitely adjusted through a designated range of,e.g., about 5° to about 10°, by pivoting one end of the disc gang abouta vertical pivot axis while permitting another end portion of the discgang to slide along a slotted plate or other unsegmented support surfacefor that end portion. The disc support beam may also be configured to beraised and lowered relative to the main beam so as to permit the cuttingdepth of the discs to be adjusted independently of the working depth ofthe remainder of the implement. The disc gang preferably is modular soas to negate the need for complex mechanical and hydraulic connectionsbetween the disc gang and the remainder of the implement.

[0044] 2. System Overview

[0045] Disc gangs constructed in accordance with the invention can beused on a variety of implements. They may be used on a standaloneimplement such as a tandem disc harrow having front and rear disc gangsets. They are particularly well suited for use in a multifunctionalseedbed preparation implement such as a Combo Mulch Finisher and,accordingly, will be described in conjunction with such a seedbedpreparation implement, it being understood that they are not limited tothat type of implement.

[0046] Referring now to FIGS. 1 and 2 a Combo Mulch Finisher implement20 incorporating disc gangs having the characteristics described aboveincludes a front disc harrow 22, a cultivator 24 located behind the discharrow and supporting the disc harrow, and a rear harrow 26 (in thiscase a tine harrow) towed behind the cultivator 24. The implement 20 istowed by a hitch 29 that extends forwardly from a mainframe 28 of thecultivator 24 and that is configured for connection to the drawbar of atractor or the like. The hitch 29 is a single strap pull clevis stylehitch with a safety chain and hitch jack (not shown). The hitch 29 islong enough to allow tight turning without interfering with the reardual or triple tractor tires.

[0047] The construction and operation of the cultivator 24 and rearharrow will now be briefly described. The construction and operation ofthe disc harrow 22 will be detailed in Section 3 below.

[0048] Still referring to FIGS. 1 and 2, the cultivator 24 is configuredto plow soil for seedbed preparation. It includes the mainframe 28,wheels 30 that support the mainframe 28 on the ground, and a pluralityof plow shanks or sweeps 32 that extend downwardly from the mainframe 28for working the soil. The wheels 30 are mounted on arms 34 that arepivotable with respect to the mainframe 28. The arms 34 are coupled to ahydraulic cylinder 36 by a suitable linkage 38 that raises and lowersthe arms 34 upon cylinder extension and retraction. The wheels 30therefore can be raised from their illustrated, lowermost position toeither 1) a partially raised position to reduce the penetration depth ofthe shanks 32 or 2) a fully raised position for transport. The typicalworking depth will vary from machine to machine and most often will bebetween 7 and 8 inches. A depth indicator (not shown) may be providedfor a quick reference on the operating depth of the cultivator.

[0049] The cultivator mainframe 28 is divided into three transverselyadjacent sections including a center section 42 and a pair of wings 44,46 that are articulated to the center section 42 by hinges 48. The wings44, 46 can flex upwardly about 10° and downwardly about 9° to followuneven terrain and contours in the field, thereby promoting consistentseedbed depth for ideal planting conditions. Each section 42, 44, 46 isformed from a plurality of longitudinally extending beams 50 and aplurality of transversely extending beams 52 interconnected to oneanother.

[0050] In the illustrated embodiment, the forwardmost beam 52 a doublesas a support for at least part of the disc harrow 22, and therearwardmost beam 52 b doubles as an articulation point for the rearharrow 26. Some of the beams 52 also support the shanks 32. Thosetransverse beams 52 that support shanks 32 are spaced longitudinallyfrom one another to form rows or “ranks.” Each of the beams 52preferably comprises a hollow rectangular tube, and those beams thatsupport the plow shanks therefore are often referred to as “rank tubes.”

[0051] The cultivator 24 of the illustrated embodiment has five ranks.The shanks 32 of successive ranks are indexed relative to the lines oftravel of the shanks of the remaining ranks to effect a so-called “splitthe middle” sweep pattern, which allows for complete tilling and theproduction of uniform ridges as described below. Of course, the numberof sections, the number of ranks, and the number of plow shanks in eachrank will vary from application to application depending, e.g., on theintended width of the tilled swath, the type of soil, and the degree ofseedbed preparation desired.

[0052] The characteristics of the particular plow shanks 32 employed fora given operation will vary depending upon the intended function of theimplement and its intended operating conditions. For moderate soilconditions where a high action spring tension shank is desired, aso-called “vibra shank” will likely be employed. In applications inwhich reduced soil disturbance and reduced fuel consumption are desired,a so-called “vibra edge shank” will likely be employed. A so-called“vibra chisel shank” will likely be employed under heavy soilconditions.

[0053] The rear harrow 26 will now be discussed with continued referenceto FIGS. 1 and 2. The harrow 26 is not necessary in many applications inwhich clod reduction and/or soil level maximization are not of concern.Where it is employed, the harrow 26 may comprise any rotary or tinestructure configured to break up clods and level ridges left by thecultivator 24. In the illustrated embodiment, the harrow 26 comprises atine harrow divided into a center, main section 54 and two end sections56, 58 that are disposed laterally adjacent the main section 54. Themain section 54 of the illustrated embodiment is wider than the twoflanking end sections 56 and 58. However, different numbers of harrowsections of different relative widths, or even a single harrow sectionspanning the width of the swath tilled by the cultivator 24, could beprovided if desired.

[0054] Still referring to FIGS. 1 and 2, each harrow section includes atleast a plurality of tines 60 and a frame that supports the tines 60.The frame preferably comprises 1) a plurality (4 in the illustratedembodiment) of tine bars 62 that support the tines 60 in longitudinallyspaced, transversely extending rows, and 2) a pair of longitudinallyextending support arms 64. The frame is coupled to the cultivatormainframe 28 by a tow arm 66 pivotably attached to the rearwardmost ranktube 52 b of the mainframe 28 by a pivoting mount 68. The tow arm 66, inturn, provides part of a parallelogram linkage mechanism that permitsthe frame to move vertically relative to the tow arm 66 whilemaintaining a parallel relationship therebetween. Each parallelogramlinkage includes a tow arm 66, a corresponding support arm 64 of theframe, and front and rear links 70, 72 connecting the support arm 64 tothe tow arm 66.

[0055] A one pass seedbed preparation operation performable by theimplement will now be described.

[0056] As the implement 20 is pulled along the soil to be worked in adraft direction, the disc harrow 22 cuts residue and turns soil asdetailed in Section 3 below. The cultivator 24 then passes over the soilworked by the disc harrow 22, with each rank of shanks 32 tilling apreviously-untilled portion of the swath worked by the shanks of thepreceding rank. Hence the shanks ahead of the rear two rows of shankstake a full cut and leave alternating strips of untilled soil. Theshanks in the next to last row till one half of the width of theremaining untilled strips and take out the middle of the ridges left bythe shanks in the row directly in front of that row. The shanks of therear row till the other half of the untilled strips and fill the groovesleft by the next to last row of shanks and take out the middle of theridge left by the shanks of the third row, resulting in a groove behindeach of the shanks of the rear row and a ridge adjacent each groove.

[0057] The harrow 26 then levels the ridges and grooves left by thecultivator 24 and reduces clods left behind by the cultivator 24. Thesoil is now ready for planting, with the desired surface residue, soiltilth, and other soil characteristics being obtained by suitableadjustments to the disc gang angle, disc penetration depth, andcultivator penetration depth.

[0058] 3. Construction and Operation of Disc Gang

[0059] Still referring to FIGS. 1 and 2, the disc harrow 22 of thecombined seedbed preparation implement 20 comprises two sets of discgangs provided on opposite sides of a line L that laterally bisects theseedbed preparation implement 20. The number of disc gangs in each setwill vary depending upon the overall width of the implement 20 and onthe length of the individual gangs. In the illustrated embodiment inwhich the implement is about 26″ wide, each set is formed from inboardand outboard disc gangs 80 and 82 that are independently mounted on themainframe 28 and independently adjustable to vary the disc gang angle.The gangs 80 and 82 of each set are located adjacent one another onopposite sides of a hinge 48 of the mainframe 28 so that the inboardgang 80 moves with the center section 42 of the mainframe 28 while theoutboard gang 82 can pivot up and down with the wing 44 or 46. Anactuator 74 is provided for effecting gang angle adjustment of each discgang 80 or 82.

[0060] The inboard and outboard gangs 80, 82 each have a first endpivotably mounted on the cultivator mainframe 28 and a second endslidably supported on the mainframe. Specifically, and referringinitially to FIGS. 3 and 9, the first or pivoting end of the outboardgang 82 is mounted on an extension 50 a of one of the inboardlongitudinal beams, and the second end is mounted on an extension of theoutwardmost longitudinal beams 50 b. The first and second ends of theinboard gang 80 are similarly mounted on a transverse beam 52 c and alongitudinal beam 50 c, respectively.

[0061] Apart from their mounting locations on the mainframe 28, theinboard and outboard disc gangs 80 and 82 of each set are identical toone another. Components of each disc gang 80, 82 therefore will bedesignated by the same reference numerals, and the same description willbe applied towards all disc gangs.

[0062] Referring now to FIGS. 3-5 and 10, the outboard disc gang 82comprises a modular unit mounted on the front end of the cultivatormainframe 28. It includes a frame 84 and a plurality of discs 86 thatare supported on the frame 84 and that ride along the ground during atillage operation. Referring to FIGS. 3-5, a plurality (9 in theillustrated embodiment) of the discs 86 are spaced along the length ofthe frame 84. Each disc 86 has a concave surface that faces thetransverse centerline L of the implement 20. All of the discs 86 aremounted on a common bolt or shaft 88 so as to rotate about a common axisthat extends at the disc gang angle. The shaft 88 is supported on theframe 84 by a pair of spaced carrier springs 90. The carrier springs 90assert a yieldable downward pressure on the discs 86 but permit limitedmovement of the discs 86 relative to the frame 84 to accommodatevariations in ground topography or the encountering of large rocks. Ascraper 92 is disposed closely adjacent the rear sides of each disc 86to scrape soil and plant residue from the associated disc 86. Thescrapers 92 are mounted on a support bar 94 clamped on the frame 84 by aplurality of longitudinally-spaced clamps 96.

[0063] Still referring to FIGS. 3-5, the frame 84 may comprise anystructure that supports the discs 86 and scrapers 92 and that permitsthe gang angle to be adjusted. The frame 84 preferably also isconfigured to permit vertical movement of the discs 86 relative to themainframe 28 to to adjust cutting depth. In the illustrated embodiment,the frame 84 includes a disc support beam 98 that supports the discs 86and a main beam 100 that mounts the disc gang 82 on the mainframe 28.The beams 98, 100 are parallel with one another and with the gang angle.Each of the beams 98 and 100 comprises a rectangular hollow tube, butI-beams, n-beams, angle-irons, or flat plates could be used as well. Theframe 84 additionally includes a pair of spaced arms 102 that connectthe breams 98, 100 to one another. The arms 102 extend in parallel withone another and transversely to the beams 98 and 100. Each arm 102comprises an n-iron, but could be formed from a tube, flat plate, etc.

[0064] Referring to FIGS. 3, 5, and 6, the front end of each of the arms102 is rigidly mounted on top of the disc support beam 98 by a bracket104. The rear end of each of the arms 102 is pivotably attached to themain beam 100 by a clevis pin assembly 106. This arrangement permits thedisc support beam 98 and discs 86 to be raised and lowered relative tothe main beam 100 to change the cutting depth for a particularcultivator depth setting. This cutting depth is adjusted by extending orretracting a hydraulic cylinder 108 operably coupled to the beams 98 and100. Specifically referring to FIGS. 6, 9, and 10, a cylinder end of thecylinder 108 is pinned to an ear mount 110 extending forwardly from anupwardly and forwardly inclined strut 112 mounted on a generally centralportion of the main beam 100. A rod end of the cylinder 108 is pivotablyattached to another ear mount 114 mounted on front of a generallycentral portion of the disc support beam 98. As best seen in FIGS. 3 and10, this relationship between the hydraulic cylinder 108 and the framecomponents 98, 100 renders the disc gang 82 as a whole modular andpermits the essentially entire disc gang 82 to be attached to or removedfrom the mainframe 28 as a unit, thereby enhancing versatility of theimplement 20 and simplifying manufacturing and assembly.

[0065] It is conceivable that gang angle adjustment could beaccommodated by a suitable connection of the disc support beam 98 to thearms 102 or of the arms 102 to the main beam 100. If depth adjustment isnot desired, it is also conceivable that this adjustment could beaccommodated by eliminating the main beam 100 and mounting the discsupport beam 98 directly on the mainframe 28 so as to accommodateangular adjustment of the disc support beam 98 relative to the mainframe28. In the illustrated embodiment, however, gang angle adjustment isaccommodated by mounting the main beam 100 on the cultivator mainframe28 so as to permit the entire frame 84 to pivot about a vertical axisthrough a gang adjust angle α (FIG. 3). The angle α typically willextend about 5°, beginning at an angle of about 5° from a perpendicularto the draft direction and ending at an angle of about 10°. However, theextent of the angular range may vary dramatically from application toapplication. To effect this gang angle adjustment, each disc gang 80, 82can be driven to pivot about the mainframe 28 by the actuator 74.

[0066] Mounting hardware for accommodating the gang angle adjustment andfor holding the disc gang 82 in its adjusted position includes a pivotpin assembly at the first end of the disc gang 82 and a sliding clampplate arrangement between the first and second ends, and preferablyadjacent the second end, of the disc gang. Referring to FIGS. 3 and 7,the pivot pin 118 extends vertically through a bore through the mainbeam 100 and through a mating bore in an ear mount 120. The ear mount120 is located beneath the main beam 100 and extends transversely fromthe foremost end of the associated transverse beam 50 a as seen in FIG.3. (The pivot pin assembly for the inboard disc gang 80 differs from theabove-described configuration only in that the pin 118 extends directlythrough the underlying transverse beam 52c rather than through aprotruding ear mount.) Referring to FIG. 8, the second end of the mainbeam 100 is mounted on an unsegmented guide that supports the beam whilepermitting the beam to pivot through the designated range. In theillustrated embodiment, the guide comprises a slotted plate 122 thatsupports a pair of angle brackets 124 so as to permit infiniteadjustment of the gang angle by sliding the brackets 124 along a slot126 in the plate 122. Specifically, a vertical leg of each angle bracket124 is welded or otherwise affixed to each side of the beam 100 so thatan elongated slot 128 in the horizontal leg of each bracket 124 overliesan orthogonally-situated elongated slot 126 in the plate 122. The plate122 is, in turn, welded to the top of the longitudinal beam 50b as seenin FIGS. 3 and 10 (the corresponding plate 122 for the inboard disc gang80 is welded to the top of the longitudinal beam 50 d, also asillustrated in FIGS. 3 and 10). Pins, such as bolts 130 extend throughthe mating slots 126 and 128 so as to ride through those slots upon discgang angle adjustment. If desired, the bolts 130 could be selectivelytightened to prevent inadvertent movement of the disc gang 82 relativeto the mainframe 28, but that tightening would not be required insituations in which the actuator 74 is capable of holding the disc gangin position.

[0067] The actuator 74 may comprise any manually operated or powereddevice that is selectively actuatable to drive the associated main beam100 to pivot about the pin 118. The actuator 74 of the illustratedembodiment comprises a turnbuckle. As best seen in FIGS. 8 and 10, theturnbuckle 74 has a rear end pivotably coupled to an ear 132 on themainframe 28 and a front end pivotably mounted to an ear mount 134 onthe rear of the main beam 100. As is conventional with turnbuckles ofthis type, manual operation of a crank 136 on the turnbuckle 74 in onedirection or the other causes the turnbuckle 74 to extend or retract,resulting in clockwise or counterclockwise pivoting of the associateddisc gang 80 or 82 about the associated pivot pin 118 and accordingly,results in gang angle adjustment. Due to the absence of any discreetmount points of the second end of the main beam 100 on the mainframe 28,this adjustment can be infinite within the desired range of gang angleadjustment rather than discreet. This in turn greatly enhances theversatility of the machine. If desired, decals (not shown) or otherindicia may be mounted on the implement 20 in the vicinity of theturnbuckle 74 so as to permit the operator to precisely obtain thedesired disc gang angle.

[0068] In operation, as the implement 20 is being pulled along the fieldto be worked by a tractor or other prime mover, the rotating discs 86cut into the soil and throw the soil inwardly towards the transversecenterline L. The depth of disc penetration for a particular cultivatorsetting can be adjusted by suitable operation of the hydraulic cylinders108. The amount of the soil turning and, accordingly, the degree of soiltilth and/or the degree of surface residue coverage remaining behind thedisc gang for a particular operating speed in particular soilconditions, is determined by the prevailing gang angle α. That angle canbe adjusted for each disc gang simply by loosening the bolts 130,turning the crank 136 to extend or retract the associated turnbuckle 74to drive the disc gang 80 or 82 to pivot about the associated pin 118,and retightening the bolts 130. Versatility is maximized by permittingthe gang angle of the individual gangs 80 and 82 of each set to beadjusted individually. For instance, it may be desirable in someinstances to set a slightly shallower disc gang angle for the inboardgang 80 of each set to prevent soil from ridging at the center of themachine. The individual adjustment made possible by the invention makes“fine tuning” for this and other purposes possible. The cutting depthsof each gang 80 and 82 of each set can also be adjusted by suitableoperation of the cylinders 108.

[0069] Many changes and modifications could be made to the inventionwithout departing from the spirit thereof. For instance, the gang angleadjustment characteristics of the present invention are applicable toimplements other than a multi component seedbed preparation implement.Those other implements include, but are not limited to, a tandemstandalone disc harrow. Different mounting arrangements could also beused for mounting the disc gangs on the mainframe of the implement, andthe disc gang frames could take other forms than that disclosed,particularly if the machine does not require cutting depth adjustmentcapability. Actuators other than turnbuckles could also be used toeffect gang angle adjustment. For instance, a double acting hydrauliccylinder could be used in place of each turnbuckle. A cylinder wouldhave the benefit of being of being capable of automatically adjustinggang angle “on the fly” with the use of appropriate sensors and controlcircuitry. If a cylinder were used, and if adjustment on the fly is notrequired, a heavier duty locking system would preferably be used inplace of the bolts to negate the need to rely on hydraulic pressure inthe cylinders to hold the disc gangs in place.

[0070] Other changes will become apparent from the appended claims.

1. A seedbed preparation implement comprising: (A) a cultivatorincluding (1) a mainframe configured to be pulled in a draft direction,and (2) a plurality of ground engaging plow shanks mounted on saidmainframe; and (B) a disc harrow including at least one disc gang, saiddisc gang including (1) a disc support beam, (2) a plurality of groundengaging discs which are rotatably supported on said disc support beamand which are configured to rotate about a common axis that extends at adisc gang angle relative to a perpendicular to said draft direction, (3)a main beam to which said disc support beam is attached and which ismounted on said mainframe so as to permit said disc gang to be movablerelative to said mainframe as a unit so as to adjust said gang angle. 2.The seedbed preparation implement as recited in claim 1, wherein saidgang angle is infinitely adjustable within at least a designated range.3. The seedbed preparation implement as recited in claim 2, wherein saiddesignated range extends from about 5° to about 10°.
 4. The seedbedpreparation implement as recited in claim 1, wherein said main beam ispivotably mounted on said mainframe adjacent a first end thereof and ismounted on a support at a location remote from said first end so as topermit said main beam to slide along an unsegmented guide on saidsupport during gang angle adjustment.
 5. The seedbed preparationimplement as recited in claim 1, further comprising an actuator that iscoupled to said disc gang and to said mainframe and that is operable topivot said disc gang about said mainframe to effect gang angleadjustment.
 6. The seedbed preparation implement as recited in claim 5,wherein said actuator comprises a turnbuckle.
 7. The seedbed preparationimplement as recited in claim 1, further comprising support arms whichcouple said main beam to said disc support beam, said support arms beingpivotable to raise and lower said disc support beam relative to saidmain beam and, thereby, adjust a cutting depth of said discs.
 8. Theseedbed preparation implement as recited in claim 1, wherein said mainbeam is mounted on a front end of said mainframe and said disc supportbeam is disposed in front of said main beam.
 9. The seedbed preparationimplement as recited in claim 8, further comprising a harrow that istowed behind said cultivator.
 10. The seedbed preparation implement asrecited in claim 1, wherein two sets of disc gangs are provided onopposite sides of a line that laterally bisects said seedbed preparationimplement, each disc gang set being formed from at least two disc gangsthat have independently adjustable gang angles.
 11. A seedbedpreparation implement comprising: (A) a generally rectangular mainframeconfigured to be pulled in a draft direction; (B) a plurality of plowshanks extending downwardly from said mainframe; and (C) at least twomodular disc gangs mounted in front of said mainframe as a unit, each ofsaid disc gangs including (1) a disc support beam located in front ofsaid mainframe and extending at a gang angle relative to a perpendicularto said draft direction, (2) a plurality of ground engaging rotary discsrotatably supported on said disc support beam, (3) a main beam whichextends in parallel with said disc support beam and which is disposedbetween said disc support beam and said mainframe, said main beam beinga) attached to said disc support beam so as to maintain said parallelrelationship therebetween and b) mounted on said mainframe so as topermit said disc gang to be movable relative to said mainframe so as topermit infinite adjustment of said gang angle within at least a rangeextending from about 5° to 10°, and (4) an actuator which is coupled tosaid disc gang and to said mainframe and which is operable to move saiddisc gang relative to said mainframe to effect gang angle adjustment.12. The seedbed preparation implement as recited in claim 11, whereinsaid main beam is pivotably mounted on said mainframe adjacent a firstend thereof and is mounted on a slotted plate at a location remote fromsaid first end so as to permit said main beam to slide along a slot insaid slotted plate for gang angle adjustment.
 13. The seedbedpreparation implement as recited in claim 11, wherein said actuatorcomprises a turnbuckle.
 14. The seedbed preparation implement as recitedin claim 11, further comprising support arms which couple said main beamto said disc support beam, said support arms being pivotable to permitsaid disc support beam to be raised and lowered relative to said mainbeam to adjust a cutting depth of said discs.
 15. The seedbedpreparation implement as recited in claim 11, wherein two sets of discgangs are provided on opposite sides of a line that laterally bisectssaid mainframe, each disc gang set being formed from at least two discgangs whose gang angles are independently adjustable.
 16. A disc gangassembly configured for attachment to a mainframe of a seedbedpreparation implement that is configured to be pulled in a draftdirection, said disc gang assembly comprising: (A) a frame which isconfigured to be connectable to the main frame; and (B) a plurality ofground engaging rotary discs which are supported on said frame and whichare configured to rotate about an axis that extends at a gang anglerelative to a perpendicular to said draft direction, wherein said frameincludes hardware configured to connect said frame relative to theimplement mainframe so as to permit said frame be movable relative tothe mainframe so as to permit said gang angle to be infinitely adjustedthrough a range of at least 3°.
 17. The disc gang assembly as recited inclaim 16, wherein said range extends from about 5° to about 10°.
 18. Thedisc gang assembly as recited in claim 16, wherein said frame ispivotably mountable on the mainframe adjacent a first end of said frameand is mountable on a slotted support of the mainframe at a locationremote from said first end so as to permit a pin depending from saidframe to slide along a slot in said slotted support for disc gang angleadjustment.
 19. The disc gang assembly as recited in claim 16, whereinsaid frame comprises a main beam which is mountable on the mainframe anda disc support beam which is located in front of said main beam, whichis connected to said main beam by a plurality of support arms, and whichsupports said discs.
 20. The disc gang assembly as recited in claim 19,wherein said support arms are pivotable to raise and lower said discsupport beam relative to said main beam and, thereby, adjust a cuttingdepth of said discs.
 21. The disc gang assembly as recited in claim 16,further comprising an actuator that is coupled to said disc gang, thatis configured to be coupled to the frame, and that is operable to movesaid disc gang relative to the mainframe to effect gang angleadjustment.
 22. A method of tilling soil comprising: (A) pulling aseedbed preparation implement in a draft direction; (B) during the step(A), plowing the soil using a plurality of plow shanks mounted on amainframe of said seedbed preparation implement; (C) during the step(A), cutting and turning the soil using a plurality of rotating discs ofa disc gang, said discs rotating about a common axis that extends at agang angle relative to a perpendicular to said draft direction, and (D)adjusting said gang angle by moving said disc gang relative to saidmainframe, the adjustment being infinite through a designated range ofat least 3°.
 23. The method as recited in claim 22, wherein the discgang angle is infinitely adjustable within at least a range extendingfrom about 5° to about 10°.
 24. The method of as recited in claim 22,wherein the adjusting step comprises pivoting one end portion of a mainbeam of said disc gang about a vertical axis while permitting a pinextending from another portion of said main beam to slide within anelongated slot on said mainframe.
 25. The method as recited in claim 22,wherein the adjusting step comprises actuating an actuator extendingbetween said main beam and said mainframe.
 26. The method as recited inclaim 24, wherein said discs are mounted on a disc support beam that isconnected to said main beam and that moves with said main beam duringgang angle adjustment, and further comprising raising and lowering saiddisc support beam relative to said main beam to adjust a cutting depthof said discs.
 27. A method of tilling soil, comprising: (A) pulling aseedbed preparation implement in a draft direction; (B) during the step(A), plowing the soil using a plurality of plow shanks mounted on amainframe of said seedbed preparation implement; (C) during the step(A), cutting and turning the soil using a plurality of rotating discs ofa disc gang, said disc gang including a main beam that is coupled to afront portion of said mainframe, and a disc support beam that is locatedin front of said main beam, that is coupled to said main beam so as tomove therewith, and that supports said discs so as to permit said discsto rotate about a common axis that extends at a gang angle relative to aperpendicular to said draft direction; and (D) adjusting said gang angleby actuating an actuator so as to pivot said main beam about a verticalaxis and thereby to cause a pin coupled to said main beam to slide alongan unsegmented guide in a plate attached to said frame.
 28. The methodas recited in claim 27, further comprising raising and lowering saiddisc support beam relative to said main beam to adjust a cutting depthof said discs.